Lithium Batterie Pack Charging Equalization Game Theory Model And Control Strategy

Currently, the use of clean energy has caused great concern in society, the demand for clean energy is increasing. The Battery technology, as an important part in the applications of clean energy, has been used widely. The battery capacity and voltage requirements are also improving to meet a variety of applications. Due to the limitations of development in traditional battery technology, it has been unable to meet the growing needs of applications. Series battery technology is the main way to solve this problem. Each battery in the battery pack couldn’t be fully consistent due to objective conditions. It may cause irreversible damage when battery works in the state of overcharge and over discharge, lead to growing differences between each battery in series, then seriously affect the use of the battery pack and may even make it early retirement. So we must use a battery pack equalization control to avoid this. The equalization process is called equalization control the battery pack.The methods to charging the battery pack into equalization are generally divided into battery voltage control and battery state of charge(SOC) control, the former is simple, but may not achieve the ultimate goal of control; the latter can be more accurate to control demand, but more difficult. There are two difficulties in SOC control method, estimating battery SOC and calculating the equalization target. In most cases, the control for each battery will affect the value of equalization target, result to the complicated mathematical calculations of balancing target and makes the control process difficult to realize. Based on the research of lithium properties, SOC estimation method, the basis of the battery equalization circuit, this paper proposes game theory as a mathematical method to find equilibrium target. The research of this paper includes:①By studying lithium principle, analyze the reasons and consequences of lithium batteries imequalization, then propose the necessity to make the lithium battery pack equalization.②Researching the lithium charging characteristics, and lithium charging process. Analysis the mainstream methods of SOC estimation currently, then the Ah integration method is chosen as the estimation method.③Based on the research of various types of charge equalization circuit, this paper selects the independent inductive equalization circuit as the basis for the game control circuit, and transform it to bidirectional current control circuit.④On the basis of Game Theory Modeling and Nash Equilibrium,this paper game modeling by time-controlled and current-control of game modeled For the equilibrium problems of bi-directional current control circuit in the battery pack.⑤This paper designed three sets of data model based on the algebraic game model, then solved its Nash Equilibrium, summed up the law and methods of Nash Equilibrium, and compared with results from other methods, verified the game model.